Azure KeyVaultErrorException: Operation returned an invalid status code ‘Forbidden’
Issue Description
Today in this article, we will cover below aspects,
Updated November 2026: a 403 troubleshooting flow (RBAC, access policy, firewall, identity), a SecretClient migration section and an FAQ.
Application using Azure KeyVault service produces below Forbidden or access denied error
Microsoft.Azure.KeyVault.Models.KeyVaultErrorException (thrown by the deprecated Microsoft.Azure.KeyVault package; the Azure.Security.KeyVault.Secrets SDK throws RequestFailedException with Status 403 instead): Operation returned an invalid status code ‘Forbidden’ at Microsoft.Azure.KeyVault.KeyVaultClient.GetSecretsWithHttpMessagesAsync(String vaultBaseUrl, Nullable`1 maxresults, Dictionary`2 customHeaders, CancellationToken cancellationToken)
Resolution
Please note that the KeyVault lets you securely access secretes and sensitive information from within your applications.
Authentication in Key Vault works using Microsoft Entra ID (formerly Azure Active Directory) where Azure AD authenticates the identity of any given security principal.
These Keys, secrets, and certificates are protected without you having to write the code yourself, and you can easily use them from your applications.
If you are getting forbidden or accessed denied error means the caller was authenticated but isn’t allowed to do the operation. The usual causes are a missing access policy or RBAC role for that identity, a different identity than you expected, or a request IP blocked by the vault firewall.
To resolve the issue please follow any of the approaches discussed below,
Approach 1 – Use Azure CLI to set up Managed Identity
Let’s see how to use Azure CLI to associate Managed ‘identity’ and policy “Principle” to the application object.
- Return to the Azure CLI
- Run the assign-identity command to create the identity for this application. This step creates required
Command
az webapp identity assign --name "<App-Service-Name>" --resource-group "<Resource-Group-Name>"
Example
az webapp identity assign --name "thecodebuzz-web-app-service" --resource-group "thecodebuzz-group"
Once executed successfully,
You shall see the output below,
{
"principalId": "4a6bdc47-xxx-4402-xxxx-fc2861108d1c",
"tenantId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
"type": "SystemAssigned"
}
As a next step, please run the below command,
Command
az keyvault set-policy --name '<key-Vault-Name>' --object-id <principalId> --secret-permissions get
Example
az keyvault set-policy --name 'thecodebuzz-key-vault' --object-id '4a6bdc47-xxxx-4402-xxxx-fc2861108d1c' secret-permissions get
Once executed successfully you will be able to resolve the issue successfully.
Approach 2 – Use Azure Portal to set up an Access policy
While creating a new Vault or using an existing KeyVault, Please make sure to choose “Select Principle” as the App service id.
- Above I have defined only “Get” access to key vault service as I want to provide only GET access to the vault. You can define more roles as needed
- For the “Select Principal” option, select the Azure Web App that you enabled Identity Management previously.
- Note- Please Choose key permission and certificate and secret permission carefully.
Once done your Vault account will be created successfully.
Approach 3 – Use Visual Studio Connected Services to set up Managed Identity
Alternatively, this can be done using Visual Studio Connected Services which is explained in detail below,
Below Under Service dependencies, Click on Configure,
Based on your configured Azure subscription, Visual Studio will list the required Key Vaults Name as shown below,
Click on Next and confirm the settings.
Note – If your Production Key Vault is running on a different Microsoft account than the Visual Studio account then you might get an error in such cases, you may need to use approach 1 or 2 or log in with the same account to overcome any such issues.
References :
That’s all! Happy coding!
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Frequently asked questions
Why does Azure Key Vault return Forbidden when I’ve already added an access policy?
A 403 means Key Vault knew who you were but refused the operation. Common causes: the vault uses Azure RBAC, so access policies are ignored; the app runs as a different identity than the one in the policy (system-assigned vs user-assigned, or two principals with the same display name); the vault firewall blocks the caller’s IP; or the change hasn’t propagated yet. Check Settings > Access configuration to see which model the vault uses, compare the object ID in the diagnostic logs with the one in the policy, and read the error body for the caller and action that were denied.
Do I need the List permission as well as Get to read a secret?
No, Get alone is enough to read a secret when you know its name. The exception is the ASP.NET Core Key Vault configuration provider, which lists secrets at startup so it can load them. Without List, it failed with this exact Forbidden exception. Grant Get and List for that case, or load specific secrets by name instead.
Why does an Owner or Contributor still get Forbidden when reading secrets?
Owner and Contributor give management-plane access to the vault resource, not data-plane access to the secrets inside it. You can manage the vault and still be refused when reading a secret. In RBAC mode, assign a data-plane role such as Key Vault Secrets User. In access policy mode, add a policy with the Get secret permission.
How long does it take for a Key Vault role or access policy change to take effect?
Allow up to about 5 minutes for RBAC propagation before you retest. A 403 right after you add an identity can be handled with a periodic retry. If the error persists beyond that, the cause is configuration, not delay. Go back to the identity, the permission model and the firewall rules.